Gantry crane PLC frequency converter and frequency converter using method

Abstract

The invention discloses a gantry crane PLC frequency converter and a frequency converter using method, and relates to the field of automation equipment.The method comprises the steps that current level information output by a photoelectric encoder and the duration time of the current level information are obtained, and the current level information is compared with adjacent level information obtained last time; determining the current tooth number of the current circle of the photoelectric encoder according to the comparison result; determining a current position angle corresponding to a grating disc in the photoelectric encoder according to the current tooth number of the current circle and the duration of the current level information; and generating a closed-loop feedback signal for the synchronous motor according to the current position angle, and performing closed-loop control on the synchronous motor by using the closed-loop feedback signal and a motor control signal of the PLC control system. Closed-loop control is carried out on the synchronous motor, so that the real-time feedback position precision and the control performance of the PLC frequency converter on the synchronous motor are improved, the safety risk of gantry crane equipment is reduced, and the service life of the gantry crane equipment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of automation equipment, and in particular to a gantry crane PLC frequency converter and a method for using the frequency converter. Background Art

[0002] Gantry crane is a kind of deformation of bridge crane. In ports, it is mainly used for loading and unloading operations of outdoor cargo yards, material yards and bulk cargo. Gantry crane has the characteristics of high site utilization, large operating range, wide adaptability and strong versatility, and is widely used in port cargo yards.

[0003] For gantry crane equipment, ordinary motors were previously used as the core power drive system. However, as time goes by, ordinary motors always keep a constant speed and cannot meet the actual operation requirements. At present, PLC-based inverters are mostly used to control the motor system equipped with gantry cranes. As a control device for electric motors, inverters can bring great convenience to the production site. It can not only adjust the speed and torque, but also save energy, and then adjust the speed of the inverter through PLC.

[0004] An encoder is a device that compiles and converts signals such as bit streams or data into a signal form that can be used for communication, transmission and storage. Simply put, an encoder can convert angular displacement or linear displacement into an electrical signal. An encoder converts the change in rotational position into an electrical signal. In other words, an encoder can be used as a position angle detection device, such as using a photoelectric encoder to calculate the position and speed information of a synchronous motor.

[0005] Due to installation and other reasons, a tooth will be removed from the photoelectric encoder. For the synchronous motor used in the gantry crane, since each tooth in the grating disk of the photoelectric encoder corresponds to a larger electrical angle, failure to address the missing tooth problem will result in a large position angle deviation. The closed-loop control of the synchronous motor requires knowing the real-time position and speed, which will cause the PLC-based inverter to have poor control performance over the motor and may even lead to production accidents.

[0006] Therefore, it is necessary to provide a PLC inverter that can cope with the above situation. Summary of the invention

[0007] In view of this, an embodiment of the present invention provides a gantry crane PLC inverter and an inverter use method, so as to solve the problem that the real-time position feedback of the synchronous motor is difficult in the case of missing tooth installation, resulting in the deterioration of the control performance of the PLC inverter on the synchronous motor.

[0008] According to the first aspect, an embodiment of the present invention provides a gantry crane PLC inverter, which is characterized by comprising: Frequency converters, PLC controllers, control panels, synchronous motors, sleep controllers and photoelectric encoders; The frequency converter is connected to the PLC controller and the synchronous motor, the control panel is connected to the PLC controller, the sleep controller is connected to the PLC controller and the synchronous motor, and the photoelectric encoder is connected to the synchronous motor.

[0009] According to a second aspect, an embodiment of the present invention further provides a method for using a frequency converter, the method comprising: According to the preset acquisition frequency, the current level information output by the photoelectric encoder and the duration of the current level information are obtained, the current level information is compared with the level information obtained in the previous adjacent time, and the current number of teeth of the current circle of the photoelectric encoder is determined according to the comparison result; Determine the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth in the current circle and the duration of the current level information; A closed-loop feedback signal for the synchronous motor is generated according to the current position angle, and the closed-loop feedback signal and the motor control signal of the PLC control system are used to perform closed-loop control on the synchronous motor.

[0010] In combination with the second aspect, in the first implementation of the second aspect, the obtaining of current level information output by the photoelectric encoder and the duration of the current level information, comparing the current level information with the level information obtained in the previous adjacent time, and determining the current number of teeth of the current circle of the photoelectric encoder according to the comparison result, specifically includes: According to the preset acquisition frequency, the level information of each output of the photoelectric encoder and the duration of each level information are obtained, and the current level information of the photoelectric encoder and the duration of the current level information are determined; If the current level information is consistent with the previous level information, the current number of teeth in the current circle remains unchanged; If the current level information is inconsistent with the previous level information, the current number of teeth in the current circle increases.

[0011] In combination with the first implementation of the second aspect, in the second implementation of the second aspect, if the current level information is inconsistent with the adjacent previous level information, the current number of teeth in the current circle is increased, specifically including: Determine whether the pulse formed by the level information obtained last time is a missing tooth pulse. If it is a missing tooth pulse, the current number of teeth in the current circle is increased by a first number, otherwise the current number of teeth in the current circle is increased by a second number; the first number is 3, and the second number is 1.

[0012] In combination with the second embodiment of the second aspect, in the third embodiment of the second aspect, the determination of whether the pulse formed by the level information previously acquired is a tooth-missing pulse includes: if the duration of the level information previously acquired exceeds twice the duration of the level information acquired before the level information previously acquired, then it is determined that the pulse formed by the level information previously acquired is a tooth-missing pulse.

[0013] In combination with the second embodiment of the second aspect, in the fourth embodiment of the second aspect, the method further includes setting a missing tooth flag, the initial missing tooth flag is set to 0, and when the pulse formed by the level information acquired last time is a missing tooth pulse, the missing tooth flag is set to 1.

[0014] In combination with the second aspect, in a fifth implementation of the second aspect, the method further includes: The running state of the synchronous motor is detected with a preset sleep cycle. When it is determined that the running state of the synchronous motor is not running within a preset time, the PLC controller generates a sleep signal of the synchronous motor.

[0015] In combination with the fifth embodiment of the second aspect, in the sixth embodiment of the second aspect, the sleep cycle is cycled in sequence of the sleep stage T1, the preparation stage T2 and the detection stage T3, the duration of the sleep stage T1 is greater than the duration of the preparation stage T2, and the duration of the preparation stage T2 is greater than the duration of the detection stage T3.

[0016] According to a third aspect, an embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any of the above-described methods for using the frequency converter are implemented.

[0017] According to a fourth aspect, an embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the above-described methods for using a frequency converter.

[0018] The gantry crane PLC inverter and inverter use method of the present invention, in the case where the photoelectric encoder is installed with missing teeth, obtains the current level information output by the photoelectric encoder and the duration of the current level information according to a preset acquisition frequency, compares the current level information with the adjacent level information obtained in the previous time, determines the current number of teeth of the current circle of the photoelectric encoder according to the comparison result, determines the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth of the current circle and the duration of the current level information, generates a closed-loop feedback signal for the synchronous motor according to the current position angle, and uses the closed-loop feedback signal and the motor control signal of the PLC control system to perform closed-loop control on the synchronous motor, thereby improving the position accuracy of real-time feedback and the control performance of the PLC inverter on the synchronous motor, thereby reducing the safety risk of the gantry crane equipment and extending the service life of the gantry crane equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings: Figure 1 A structural schematic diagram showing a method for using a PLC frequency converter provided by the present invention is shown; Figure 2 A schematic flow chart of a method for using a frequency converter provided by the present invention is shown; Figure 3 It is a schematic diagram of the hardware structure of the electronic device provided in the embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 In this embodiment, the operating system of the gantry crane is mainly composed of a frequency converter, a PLC controller, a control panel and a synchronous motor. The operator generates various operating instructions for operating the gantry crane through the operating system connected to the gantry crane.

[0022] Among them, the PLC controller adopts EtherCAT communication mode and automatic slave address allocation. The PLC controller and the control panel adopt Ethernet communication mode. The default Ethernet address of the PLC controller is 192.168.1.88. Correspondingly, the default address of the touch screen is 192.168.1.100.

[0023] Preferably, the control panel uses a touch screen that is more convenient for operators to operate. The PLC controller has the following modules: Power supply unit: GL10-PS2 model device is selected; CPU unit: Use AC81X-0122-U0R0 model device (AC810); Slave unit: select GL10-RTU-ECTA model device; Input unit: GL10-1600END model device is selected. Output unit: Use GL10-0016ER model device.

[0024] For gantry crane equipment, ordinary motors were previously used as the core power drive system. However, as time goes by, ordinary motors always keep a constant speed and cannot meet the actual operation requirements. At present, PLC-based inverters are mostly used to control the motor system equipped with gantry cranes. As a control device for electric motors, inverters can bring great convenience to the production site. It can not only adjust the speed and torque, but also save energy, and then adjust the speed of the inverter through PLC.

[0025] An encoder is a device that compiles and converts signals such as bit streams or data into a signal form that can be used for communication, transmission and storage. Simply put, an encoder can convert angular displacement or linear displacement into an electrical signal. An encoder converts the change in rotational position into an electrical signal. In other words, an encoder can be used as a position angle detection device, such as using a photoelectric encoder to calculate the position and speed information of a synchronous motor.

[0026] Due to installation and other reasons, one tooth will be removed from the photoelectric encoder. For the synchronous motor used in the gantry crane, such as the permanent magnet synchronous motor used in this embodiment, since each tooth in the grating disk of the photoelectric encoder corresponds to a larger electrical angle, if the missing tooth problem is not handled, it will cause a large position angle deviation. The closed-loop control of the synchronous motor requires knowing the real-time position and speed, which will result in poor control performance of the motor and even cause production accidents.

[0027] Therefore, the photoelectric encoder includes a grating disk and a photoelectric detection device, wherein the grating disk is configured to rotate driven by the output shaft of the synchronous motor; and the photoelectric detection device is configured to output corresponding level information according to the rotation of the grating disk; The memory stores program codes that can be executed by the controller. When the program codes are executed by the controller, the current position angle of the grating disk in the photoelectric encoder is determined based on the position calculation method based on the synchronous motor photoelectric encoder in the first embodiment according to the level information output by the photoelectric detection device in the grating encoder; The controller is also configured to perform closed-loop control on the synchronous motor according to the current position angle of the grating disk in the photoelectric encoder.

[0028] Among them, the controller has both control and execution functions.

[0029] The PLC inverter also includes a sleep controller, which detects the operating state of the synchronous motor in a preset sleep cycle. When it is determined that the operating state of the synchronous motor is not running within a preset time, the PLC controller generates a sleep signal for the synchronous motor.

[0030] In this embodiment, the time of the preparation stage T2 and the time of the detection stage T3 are both much shorter than the time of the sleep stage T1, and the time of the detection stage T3 is shorter than the time of the preparation stage T2. For example, the time of the sleep stage T1 is 500ms, the time of the preparation stage T2 is 1ms, and the time of the detection stage T3 is 50us. Since the sleep stage T1>>>>preparation stage T2>detection stage T3, correspondingly, the average power consumption of the sleep stage T1>>>>the average power consumption of the preparation stage T2>the average power consumption of the detection stage T3, in the present invention, based on the time setting of the three stages, the RFID reader is in the sleep stage T1 most of the time, and the power consumption at this time is the lowest. The power consumption of the detection stage T3 is the largest, but the time of this stage is also the shortest. The sleep stage T1 and the preparation stage T2 under ultra-low power consumption greatly reduce the energy consumption of the sleep controller.

[0031] In order to solve the above problems, a method for using a frequency converter is provided in this embodiment, aiming to improve the accuracy of the position angle of real-time feedback, thereby improving the control accuracy of the PLC frequency converter on the synchronous motor, thereby reducing the safety risk of the gantry crane equipment and extending the service life of the gantry crane equipment. The method for using a frequency converter in the embodiment of the present invention can be used in electronic devices, including but not limited to computers, mobile terminals, etc. Figure 2 is a flow chart of a method for using a frequency converter according to an embodiment of the present invention. Figure 2 As shown, the method may include the following steps: S10, obtaining the current level information output by the photoelectric encoder and the duration of the current level information according to the preset acquisition frequency, comparing the current level information with the level information obtained in the previous adjacent time, and determining the current number of teeth of the current circle of the photoelectric encoder according to the comparison result.

[0032] S20, determining a current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth of the current circle and the duration of the current level information.

[0033] S30, generating a closed-loop feedback signal for the synchronous motor according to the current position angle, and performing closed-loop control on the synchronous motor using the closed-loop feedback signal and a motor control signal of a PLC control system.

[0034] For the grating disk of the photoelectric encoder, 1 represents that when the light-emitting element illuminates this position, the output pulse is a high level, and 0 represents that when the light-emitting element illuminates this position, the output pulse is a low level. When the motor is not rotating, the output is a fixed high level signal or a low level signal. When the motor rotates at a certain speed, the output is an alternating high and low level signal of equal duration.

[0035] One circle of the grating disk of the photoelectric encoder is In radians, if there is no missing tooth, let the number of motor pole pairs be P, the number of grating slots be N, and the electrical angle be P times the mechanical angle, then the electrical angle corresponding to each slot is .

[0036] Since the change of level information will affect the change of the number of teeth of the photoelectric encoder, the current level information obtained in real time is compared with the level information obtained last time, and the current number of teeth n of the photoelectric encoder is determined according to the comparison result, which is divided into the following two cases: If the current level information is consistent with the level information obtained last time, the current number of teeth n remains unchanged; If the current level information is inconsistent with the level information obtained last time, the current tooth number n is increased, the duration of the level information obtained last time is recorded, and the duration of the current level information is set to 0.

[0037] In the case where the current level information obtained in real time is inconsistent with the level information obtained last time, if the photoelectric encoder tooth slots are complete, when the level information changes, you only need to add 1 to the current tooth number n. Since the current level information has just changed, the duration of the current level information is set to 0.

[0038] Due to the limitation of photoelectric encoder installation, there may be a situation where one tooth of the photoelectric encoder is removed. Therefore, when the level information changes, in the case of missing teeth, the grating disk may have run an extra tooth angle. Therefore, the current number of teeth is not just 1 plus 1 based on the number of teeth obtained last time, but needs to be 2 plus the number of teeth obtained last time. The specific judgment method is that if the duration of the level information obtained last time exceeds 2 times the duration of the level information obtained before the last level information obtained, it is judged that the pulse formed by the level information obtained last time is a missing tooth pulse, that is, the pulse formed by the level information obtained last time has missing teeth.

[0039] In addition, since the number of grating slots of the photoelectric encoder is N, when the motor rotates one circle, the number of teeth of the photoelectric encoder reaches N, which needs to be cleared, and then the calculation cycle continues. However, due to the existence of missing teeth, if the missing teeth occur at the zero position, the current number of teeth when the motor rotates one circle cannot reach N. Therefore, it is unreasonable to clear the number of teeth when the current number of teeth is N. In order to prevent the zero-degree positioning from being set at the position of the missing tooth pulse, a missing tooth flag is added. When it is determined that a missing tooth pulse is encountered, the missing tooth flag is set to 1. If the missing tooth flag is 1, the current number of teeth n is cleared when the current number of teeth n is greater than N, that is, there is no missing tooth at the zero position at this time; if the missing tooth flag is always 0, the current number of teeth n is cleared when the current number of teeth n is greater than N-2.

[0040] Since the photoelectric encoder does not have an absolute zero position, in order to determine the absolute zero position, the motor is initially positioned by passing direct current through the motor, and the motor's rotor shaft is pulled to the position of the motor's A-phase axis. The position angle at this time is defined as the zero position.

[0041] When the motor rotates, the current level information output by the photoelectric detection device in the photoelectric encoder is obtained in real time and the duration t of the current level information is recorded. The current level information obtained in real time is compared with the level information obtained last time, and the current number of teeth n of the photoelectric encoder is determined according to the comparison result; the current position angle of the grating disk in the photoelectric encoder is determined according to the current number of teeth n and the duration t of the current level information.

[0042] More specifically, the current position angle The calculation formula is:

[0043] in, Indicates the motor speed, Indicates the number of motor pole pairs, represents the number of grating grooves, Indicates a persistence event for the current level.

[0044] It should be noted that It represents the sum of the number of zones 0 and 1. Assuming that the electrical angle is P times the mechanical angle, the electrical angle corresponding to each slot / tooth is . This does not refer to zone 1 or zone 0; it refers to the number of slots / teeth obtained in this embodiment. In addition, since the number of grating slots of the photoelectric encoder is , when the motor rotates one circle, the number of slots / teeth of the photoelectric encoder needs to be cleared when it reaches zero. In particular, if there is a missing tooth, the current number of teeth n will be cleared when n is greater than -2. In this embodiment, the subsequent calculation will continue in a loop. Since the photoelectric encoder does not have an absolute zero position, in order to determine the absolute zero position, in this embodiment, the method of positioning the motor through DC is used at the beginning to pull the rotor shaft of the motor to the position of the axis of phase A of the motor. The position angle at this time is set to zero. In this embodiment, by clearing the current number of teeth n, the position angle can be controlled between 0-2 to avoid the output position angle exceeding 2. The low-level output time for the missing tooth slot is the time of three normal slots, and the corresponding electrical angle is If the missing teeth are not taken into account, a large error will occur in the position angle calculation.

[0045] In fact, for a photoelectric encoder with a grating disk, area 1 represents the light-transmitting area of ​​the grating disk, and area 0 represents the light-shielding area of ​​the grating disk. In this embodiment, the grating disk is divided into toothed grooves and non-toothed grooves. Among them, when the light-emitting element illuminates the position of the toothed groove, the output pulse is a high level, which is area 1; when the light-emitting element illuminates the position of the non-toothed groove, the output pulse is a low level, which is area 0; when the motor does not rotate, the output is a fixed high-level signal or a low-level signal; when the motor rotates at a certain speed without missing teeth, the output is an alternating high-low level signal of equal duration; in the case of missing teeth, if the toothed groove between two non-toothed grooves needs to remove its teeth in some special cases, then a tooth-missing groove will appear, which is equal to non-toothed groove 1 + toothed groove with teeth removed + non-toothed groove 3. Therefore, the low-level output time of the tooth-missing groove is the time of three normal grooves, and the corresponding electrical angle is.

[0046] Assuming that the number of slots / teeth of a photoelectric encoder with a grating disk is 36, if there are no missing teeth, there are 18 toothed slots and 18 non-toothed slots, that is, 18 1 zones and 18 0 zones. Figure 2 In the case of missing teeth shown, there are 17 toothed grooves and 19 non-toothed grooves, that is, 17 1 zones and 19 0 zones, while in actual situation, there are 17 toothed grooves, 16 non-toothed grooves and 1 missing tooth groove, that is, by reading the level information, the grating disk shows 17 1 zones and 17 0 zones (0 zone includes 16 0 zones with a level output time of one normal groove and 1 0 zone with a level output time of three normal grooves).

[0047] The method for using the frequency converter of the present invention, in the case where the photoelectric encoder is installed with missing teeth, obtains the current level information output by the photoelectric encoder and the duration of the current level information according to a preset acquisition frequency, compares the current level information with the adjacent level information obtained in the previous time, determines the current number of teeth of the current circle of the photoelectric encoder according to the comparison result, determines the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth of the current circle and the duration of the current level information, generates a closed-loop feedback signal for the synchronous motor according to the current position angle, and uses the closed-loop feedback signal and the motor control signal of the PLC control system to perform closed-loop control on the synchronous motor, thereby improving the position accuracy of real-time feedback and the control performance of the PLC frequency converter on the synchronous motor, thereby reducing the safety risk of the gantry crane equipment and extending the service life of the gantry crane equipment.

[0048] Figure 3 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 3 As shown, the electronic device may include: a processor 310 (processor), a communication interface 320 (Communications Interface), a memory 330 (memory) and a communication bus 340, wherein the processor 310, the communication interface 320, and the memory 330 communicate with each other through the communication bus 340. The processor 310 may call the logic command in the memory 330 to execute the inverter use method, which includes: According to the preset acquisition frequency, the current level information output by the photoelectric encoder and the duration of the current level information are obtained, the current level information is compared with the level information obtained in the previous adjacent time, and the current number of teeth of the current circle of the photoelectric encoder is determined according to the comparison result; Determine the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth in the current circle and the duration of the current level information; A closed-loop feedback signal for the synchronous motor is generated according to the current position angle, and the closed-loop feedback signal and the motor control signal of the PLC control system are used to perform closed-loop control on the synchronous motor.

[0049] In addition, the logic instructions in the above-mentioned memory 330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memor), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0050] On the other hand, the present invention further provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer, the computer can execute the inverter use method provided by the above methods, the method comprising: According to the preset acquisition frequency, the current level information output by the photoelectric encoder and the duration of the current level information are obtained, the current level information is compared with the level information obtained in the previous adjacent time, and the current number of teeth of the current circle of the photoelectric encoder is determined according to the comparison result; Determine the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth in the current circle and the duration of the current level information; A closed-loop feedback signal for the synchronous motor is generated according to the current position angle, and the closed-loop feedback signal and the motor control signal of the PLC control system are used to perform closed-loop control on the synchronous motor.

[0051] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for using the frequency converter provided above is implemented, and the method comprises: Obtain a target image of the user in the driving scene, and input the target image into a trained autonomous driving model to obtain a target trajectory output by the autonomous driving model, and obtain an autonomous driving control instruction from the target trajectory; the target image includes obstacle targets, traffic markings, and traffic signals; According to the preset acquisition frequency, the current level information output by the photoelectric encoder and the duration of the current level information are obtained, the current level information is compared with the level information obtained in the previous adjacent time, and the current number of teeth of the current circle of the photoelectric encoder is determined according to the comparison result; Determine the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth in the current circle and the duration of the current level information; A closed-loop feedback signal for the synchronous motor is generated according to the current position angle, and the closed-loop feedback signal and the motor control signal of the PLC control system are used to perform closed-loop control on the synchronous motor.

[0052] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gantry crane PLC inverter. Characterized by: include: Frequency converters, PLC controllers, control panels, synchronous motors, sleep controllers and photoelectric encoders; The frequency converter is connected to the PLC controller and the synchronous motor, the control panel is connected to the PLC controller, the sleep controller is connected to the PLC controller and the synchronous motor, and the photoelectric encoder is connected to the synchronous motor.

2. A method for using a frequency converter implemented by the gantry crane PLC frequency converter according to claim 1, characterized in that: The method comprises: According to the preset acquisition frequency, the current level information output by the photoelectric encoder and the duration of the current level information are obtained, the current level information is compared with the level information obtained in the previous adjacent time, and the current number of teeth of the current circle of the photoelectric encoder is determined according to the comparison result; Determine the current position angle corresponding to the grating disk in the photoelectric encoder according to the current number of teeth in the current circle and the duration of the current level information; A closed-loop feedback signal for the synchronous motor is generated according to the current position angle, and the closed-loop feedback signal and the motor control signal of the PLC control system are used to perform closed-loop control on the synchronous motor.

3. The method for using a frequency converter according to claim 2, characterized in that: The step of obtaining the current level information output by the photoelectric encoder and the duration of the current level information, comparing the current level information with the level information obtained in the previous adjacent time, and determining the current number of teeth of the current circle of the photoelectric encoder according to the comparison result, specifically includes: According to the preset acquisition frequency, the level information of each time output by the photoelectric encoder and the duration of each level information are obtained, and the current level information of the photoelectric encoder output and the duration of the current level information are determined; If the current level information is consistent with the previous level information, the current number of teeth in the current circle remains unchanged; If the current level information is inconsistent with the previous level information, the current number of teeth in the current circle increases.

4. The method for using a frequency converter according to claim 3, characterized in that: If the current level information is inconsistent with the previous level information, the current number of teeth in the current circle will increase, including: Determine whether the pulse formed by the level information obtained last time is a missing tooth pulse. If it is a missing tooth pulse, the current number of teeth in the current circle is increased by a first number, otherwise the current number of teeth in the current circle is increased by a second number; the first number is 3, and the second number is 1.

5. The method for using a frequency converter according to claim 4, characterized in that: The determining whether the pulse formed by the level information acquired last time is a tooth-missing pulse includes: if the duration of the level information acquired last time exceeds twice the duration of the level information acquired before the level information acquired last time, determining that the pulse formed by the level information acquired last time is a tooth-missing pulse.

6. The method for using a frequency converter according to claim 4, characterized in that: The method further includes setting a missing tooth flag, wherein the initial missing tooth flag is set to 0, and when a pulse formed by the level information acquired last time is a missing tooth pulse, the missing tooth flag is set to 1.

7. The method for using a frequency converter according to claim 2, characterized in that: The method further comprises: The operation state of the synchronous motor is detected with a preset sleep cycle. When it is determined that the operation state of the synchronous motor is not running within a preset time, the PLC controller generates a sleep signal of the synchronous motor.

8. The method for using a frequency converter according to claim 7, characterized in that: The sleep cycle is a cycle of a sleep phase T1, a preparation phase T2 and a detection phase T3 in sequence. The duration of the sleep phase T1 is longer than the duration of the preparation phase T2, and the duration of the preparation phase T2 is longer than the duration of the detection phase T3.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method for using the frequency converter as claimed in any one of claims 1 to 7 are implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for using the frequency converter as claimed in any one of claims 1 to 7 are implemented.

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